Superconductivity with a critical temperature \(T_c\sim 10K\)  was discovered recently in a series of infinite-layer nickelate materials synthesized by topotactic reduction (R\(_{1-x}\) Sr\(_{x}\) NiO\(_2\) , where \(R\)  = La, Nd, Pr) [1]}, [2]}, [3]}, [4]}, [5]}. In these materials, Ni and O form quasi-two-dimensional square-planar structures with the rare-earth element serving as a charge reservoir spacer-layer. These materials are isostructural to infinite-layer cuprates, such as CaCuO\(_2\) , and also should share close electronic properties, as formal valence counting indicates Ni\(^{1+}\)  with a 3\(d^9\)  configuration resembling that of Cu\(^{2+}\) . Thus, understanding the physics of these recently synthesized compounds should shed light on the fundamental mechanism of unconventional superconductivity in cuprates and similar materials.
